1. Field of the Invention
The present invention concerns a lamination system for thermocompression bonding of a transparent film on a surface of a card such as an ID card.
2. Description of the Prior Art
In a conventional lamination system, a transparent film cut into a predetermined size and mounted on a base sheet (a carrier) is torn off from the base sheet and is laminated on a surface of a card by thermocompression bonding. Such lamination system is undesirable in view of the operation cost and the protection of environment, since the base sheet used is thrown away as waste material.
To solve such problem, a wasteless type lamination system has been developed and is being practically used.
In the wasteless type lamination system, a leading edge of a continuous transparent laminate film is drawn out from a supply roll; then, transferred along a film transfer path; then, cut in a predetermined length by a cutter; and then, further transferred along the film transfer path until the laminate film reaches a point of convergence where it meets a printed card.
On the other hand, the printed card put into the lamination system from a card printer is transferred to the point of convergence along a card transfer path.
At the point of convergence, the cut laminate film is laid on the printed card, and then, the cut laminate film and the printed card are further transferred to a thermocompression bonding place where the cut laminate film is laminated on the surface of the printed card by thermocompression bonding using a heat roller provided there.
Such wasteless type lamination system is advantageous in view of the operation cost and the protection of environment, since the laminate film is used after being cut in a necessary length and the base sheet is not used.
Further, a dual sided wasteless lamination system by which both surfaces of a card can be laminated simultaneously has been disclosed.
In the wasteless type lamination system of the prior art as explained above, a card sometimes warps after lamination. However, means or method for properly rectifying a warp in a laminated card has not been disclosed, or a disclosed one applies only a rectification force uniform in the longitudinal direction of the warped card using rollers having lengths corresponding to the width of the card. Accordingly, there has been a problem that warped laminated cards are sometimes not sufficiently rectified, depending on the characteristics of the laminate film used. Warped laminated cards are liable to be produced particularly in dual sided wasteless type lamination systems. A warp in a card may cause read/write error of magnetic data, or read error of bar code data. It also deteriorates the quality of the laminated card.